diff --git a/core/libs/prx/libkernel/Pthread/src/Thread.cpp b/core/libs/prx/libkernel/Pthread/src/Thread.cpp
index b27a79bb5e..cba281fd82 100644
--- a/core/libs/prx/libkernel/Pthread/src/Thread.cpp
+++ b/core/libs/prx/libkernel/Pthread/src/Thread.cpp
@@ -830,9 +830,9 @@ int APS5_VABI scePthreadCreate(Pthread* thread, const PthreadAttr* attr, Pthread
 
 int APS5_VABI scePthreadJoin(Pthread thread, void** retval) {
     if (!thread) return SCE_KERNEL_ERROR_EINVAL;
+    if (thread == CurrentGuestState().current) return SCE_KERNEL_ERROR_EDEADLK;
     if (thread->_detached) return SCE_KERNEL_ERROR_EINVAL;
     if (thread->_joined.load(std::memory_order_acquire)) return SCE_KERNEL_ERROR_ESRCH;
-    if (thread == CurrentGuestState().current) return SCE_KERNEL_ERROR_EDEADLK;
     ThreadCancel::Check();
     {
         std::unique_lock lock(thread->_join_mtx);
diff --git a/core/libs/tests/GuestPthreadJoinSelf.cpp b/core/libs/tests/GuestPthreadJoinSelf.cpp
index 742fa9d734..2fec26bef7 100644
--- a/core/libs/tests/GuestPthreadJoinSelf.cpp
+++ b/core/libs/tests/GuestPthreadJoinSelf.cpp
@@ -1,12 +1,16 @@
 #include "SceTypes.hpp"
+#include <atomic>
+#include <chrono>
 #include <cstdint>
 #include <cstdlib>
+#include <thread>
 
 extern "C" {
 int APS5_VABI scePthreadCreate(Pthread* thread, const PthreadAttr* attr, PthreadEntry entry, void* arg, const char* name);
 int APS5_VABI scePthreadJoin(Pthread thread, void** retval);
 Pthread APS5_VABI scePthreadSelf(void);
 int APS5_VABI pthread_join_nid_postfix(Pthread thread, void** retval);
+int APS5_VABI scePthreadDetach(Pthread thread);
 }
 
 static constexpr int SCE_OK = 0;
@@ -23,6 +27,18 @@ static void* APS5_VABI JoinSelf(void*) {
     return reinterpret_cast<void*>(std::uintptr_t{0x1234});
 }
 
+static std::atomic<int> detachedChecks{0};
+
+static void* APS5_VABI DetachThenJoinSelf(void*) {
+    void* result = reinterpret_cast<void*>(std::uintptr_t{0x66});
+    Require(scePthreadDetach(scePthreadSelf()) == SCE_OK);
+    Require(scePthreadJoin(scePthreadSelf(), &result) == SCE_KERNEL_ERROR_EDEADLK);
+    Require(pthread_join_nid_postfix(scePthreadSelf(), &result) == GUEST_EDEADLK);
+    Require(result == reinterpret_cast<void*>(std::uintptr_t{0x66}));
+    detachedChecks.store(1);
+    return nullptr;
+}
+
 int main() {
     Pthread thread = nullptr;
     void* result = nullptr;
@@ -36,4 +52,14 @@ int main() {
     Require(scePthreadCreate(&thread, &unset, JoinSelf, nullptr, "unset-attr") == SCE_OK);
     Require(scePthreadJoin(thread, &result) == SCE_OK);
     Require(result == reinterpret_cast<void*>(std::uintptr_t{0x1234}));
+
+    thread = nullptr;
+    Require(scePthreadCreate(&thread, nullptr, DetachThenJoinSelf, nullptr, "detach-join-self") == SCE_OK);
+    for (int wait = 0; wait < 5000 && detachedChecks.load() == 0; ++wait) std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    Require(detachedChecks.load() == 1);
+
+    result = reinterpret_cast<void*>(std::uintptr_t{0x77});
+    Require(scePthreadJoin(scePthreadSelf(), &result) == SCE_KERNEL_ERROR_EDEADLK);
+    Require(pthread_join_nid_postfix(scePthreadSelf(), &result) == GUEST_EDEADLK);
+    Require(result == reinterpret_cast<void*>(std::uintptr_t{0x77}));
 }
diff --git a/core/libs/tests/GuestThreadSelf.cpp b/core/libs/tests/GuestThreadSelf.cpp
index 9c59471e91..c94f557187 100644
--- a/core/libs/tests/GuestThreadSelf.cpp
+++ b/core/libs/tests/GuestThreadSelf.cpp
@@ -110,7 +110,8 @@ int main() {
     Require(pthread_getthreadid_np_nid_postfix() == static_cast<int>(mainTid));
     int local = 0;
     Require(StackContains(mainSelf, &local));
-    Require(scePthreadJoin(mainSelf, nullptr) == SCE_KERNEL_ERROR_EINVAL);
+    Require(scePthreadJoin(mainSelf, nullptr) == SCE_KERNEL_ERROR_EDEADLK);
+    Require(pthread_join_nid_postfix(mainSelf, nullptr) == GUEST_EDEADLK);
     Require(scePthreadDetach(mainSelf) == SCE_KERNEL_ERROR_EINVAL);
     Require(scePthreadJoin(nullptr, nullptr) == SCE_KERNEL_ERROR_EINVAL);
     Require(scePthreadDetach(nullptr) == SCE_KERNEL_ERROR_EINVAL);